A wireless device (e.g., a cellular phone or a smart phone) may include multiple transmitters and receivers to support two-way communication. Many wireless devices are configured to simultaneously operate on multiple different frequencies. A wireless device may be configured to communicate with another station via combinations low, medium, or high frequency bands. Each frequency band generally requires a dedicated antenna system within the wireless device. The location of an antenna system within the device may have a substantial impact on the output power of the corresponding transmitter. For example, antenna systems located near the ear of a user may be power limited in an effort to minimize the user's exposure to radio frequency emissions. A Specific Absorption Rate (SAR) index is used to measure the rate at which energy is absorbed by the human body when exposed to a radio frequency electromagnetic field. The Federal Communications Commission (FCC) establishes limits for SAR and many wireless devices implement transmitter power limits based on feedback from a proximity sensor.